fix(types): data matcher for body and query. (#1725)

* fix(types): data matcher for body and query.

Fixes: #1724
Closes: #1723

Updates the JSONish type using inspiration from the thread on adding a
JSON type to TS. microsoft/TypeScript#1897 (comment)

This change does a couple sublet things:
- Adds `undefined` to scalar values allowed in arrays or as values in objects.
  This allows for interfaces with optional keys to be passed in. ref #1723
- Splits out top-level array and objects into their interfaces so they could be used directly.
  Allows enforcing non-arrays for `.query`.
- `RequestBodyMatcher` now extends the array and map types instead of the raw `DataMatcher`.
  Allowing arrays fixes #1724.
  This also ensures that booleans, numbers, and `null` are not considered valid.

types/index.d.ts

@@ -37,23 +37,29 @@ declare namespace nock {
     interceptorOptions?: Options
   ) => Interceptor
 
-  // essentially valid decoded JSON with the addition of possible RegExp
-  interface DataMatcher {
-    [k: string]:
-      | boolean
-      | null
-      | number
-      | string
-      | RegExp
-      | DataMatcher
-      | Array<boolean | null | number | string | RegExp | DataMatcher>
+  // Essentially valid, decoded JSON with the addition of possible RegExp. TS doesn't currently have
+  // a great way to represent JSON type data, this data matcher design is based off this comment.
+  // https://github.com/microsoft/TypeScript/issues/1897#issuecomment-338650717
+  type DataMatcher =
+    | boolean
+    | number
+    | string
+    | null
+    | undefined
+    | RegExp
+    | DataMatcherArray
+    | DataMatcherMap
+  interface DataMatcherArray extends Array<DataMatcher> {}
+  interface DataMatcherMap {
+    [key: string]: DataMatcher
   }
 
   type RequestBodyMatcher =
     | string
     | Buffer
     | RegExp
-    | DataMatcher
+    | DataMatcherArray
+    | DataMatcherMap
     | { (body: any): boolean }
 
   type RequestHeaderMatcher =
@@ -128,7 +134,7 @@ declare namespace nock {
       matcher:
         | boolean
         | string
-        | DataMatcher
+        | DataMatcherMap
         | URLSearchParams
         | { (parsedObj: ParsedUrlQuery): boolean }
     ): this

types/tests.ts

@@ -5,12 +5,14 @@ import { URL, URLSearchParams } from 'url'
 let scope: nock.Scope = nock('http://example.test')
 let inst: nock.Interceptor
 let str = 'foo'
-let strings: string[]
+let strings = ['foo', 'bar']
 let defs: nock.Definition[]
 let options: nock.Options = {}
 
+const buffer = Buffer.from('')
 const num = 42
 const obj: { [k: string]: any } = {}
+const objWithUndefinedValue: { a: string; b?: string } = { a: 'a' }
 const regex = /test/
 
 scope.head(str) // $ExpectType Interceptor
@@ -34,6 +36,16 @@ inst = scope.post(str, str)
 inst = scope.post(str, str, options)
 inst = scope.post(str, obj)
 inst = scope.post(str, regex)
+inst = scope.post(str, objWithUndefinedValue)
+inst = scope.post(str, str)
+inst = scope.post(str, strings)
+inst = scope.post(str, [num, str, regex])
+inst = scope.post(str, [num, num, num])
+inst = scope.post(str, regex)
+inst = scope.post(str, buffer)
+inst = scope.post(str, true) // $ExpectError
+inst = scope.post(str, null) // $ExpectError
+inst = scope.post(str, num) // $ExpectError
 
 inst = scope.put(str)
 inst = scope.put(str, str)
@@ -53,8 +65,13 @@ inst = scope.merge(str, str, options)
 inst = scope.merge(str, obj)
 inst = scope.merge(str, regex)
 
-inst = inst.query(obj)
 inst = inst.query(true)
+inst = inst.query(obj)
+inst = inst.query(objWithUndefinedValue)
+inst = inst.query({ foo: regex })
+inst = inst.query(strings) // $ExpectError
+inst = inst.query(buffer) // $ExpectError
+inst = inst.query(regex) // $ExpectError
 
 inst = scope.intercept(str, str)
 inst = scope.intercept(str, str, str)